Detergent compositions

ABSTRACT

An opaque liquid detergent composition comprises (a) one or more synthetic detergents, and (b) an aqueous dispersion of a water and alkali insoluble homopolymer of styrene or substituted styrene, or a water and alkaliinsoluble copolymer thereof with a minor proportion by weight of one or more copolymerizable monomers; (a) may be anionic in nature, e.g. soap, an alkylbenzene sulphonate, a primary or sec.-alkyl sulphate or a sulphated alkylphenol-ethylene oxide condensate, all suitably present as the sodium or ammonium salts, nonionic, e.g. a fatty acid mono- or di-alkanolamide, or an ethylene oxide condensate with an alkylphenol, a fatty alcohol or a fatty acid, or cationic, e.g. an alkyl-trimethylammonium, alkylpyridinium or alkyldimethylarylammonium halide.  The styrene monomer used in (b) may be substituted with alkyl, alkoxy or halo groups, and may be copolymerized with 1-25% of such substances as acrylamide, methacrylamide, acrylic and methacrylic acids and esters thereof, acrylo- and methacrylo-nitriles, butadiene or maleic acid. In general, (b) comprises 0.01-5% by weight of the composition, and the majority of the polymer particles have diameters of 0.1-4 m  in the dispersion.  Yetrasodium pyrophosphate, sodium, potassium, ammonium and alkanolamine hexametaphosphates, penton sodium tripolyphosphate, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic or polymethacrylic acid salts, starch or its derivatives, sodium xylene sulphate, ethanol, glycerol, optical whiteness, colour and foaming agents may slso be incorporated.

United States Patent 3,326,807 DETERGENT COMPOSITIONS Dorothy Joyce Guest and William Ian Williamson, Manchester, England, assignors to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain N0 Drawing. Filed Jan. 31, 1964, Ser. No. 341,745 Claims priority, application Great Britain, Feb. 15, 1963, 6,209/63 1 Claim. (Cl. 252-152) The present invention relates to liquid detergent compositions which contain an opacifying agent and which are of particular value as detergent toilet preparations.

For toilet purposes, such as for example washing the hands, it has formerly been most customary to employ a tablet of high quality soap which consists usually of the sodium and potassium salts of certain purified fatty acids. Such soaps have the advantage that they are pleasant to the touch and provide adequate foam during the process of washing.

The use of a tablet of soap has however a number of disadvantages. For example when the water is hard an insoluble scum is formed which deposits on the skin and such conditions are unpleasant to the touch. Further, when the soap is in contact with water whilst not in use it is liable to soften, thus leaving undesirable soap residues in the soap container; and in addition the bulk of the soap may be inconvenient to the washing process.

In order to alleviate some of these disadvantages certain liquid soaps have been employed which may comprise for example the potassium salts of certain pure fatty acids and which may be contained for example in a vessel which is enabled to dispense the liquid when required. These liquid soaps are still unsatisfactory in certain respects however, particularly in that they allow the formation of insoluble scum deposits with hard water.

With the advent of the synthetic detergents it was natural that they should be considered for the preparation of detergent toilet compositions since amongst their advantages over soap they do not form insoluble scum deposits with hard water. However, the synthetic detergents when used alone for this purpose are inadequate in that they are generally deficient in foaming power and they may impart a somewhat unpleasant sensation when used in contact with the skin since they do not possess the unctuous properties of the soaps.

It is therefore desirable that synthetic detergent liquids used for toilet purposes should be of an unctuous nature. It is found that such liquids are particularly desirable when they have the appearance and give the sensation to the skin of a hand lotion, that is they are opaque and have a creamy consistency.

We have not found that the appearance which is associated with the hand lotion may be imparted to a liquid synthetic detergent by incorporating in the detergent an aqueous dispersion of a polymer of styrene or of a substituted styrene or of certain copolymers thereof.

Thus according to the present invention we provide an opaque liquid detergent composition which contains a liquid synthetic detergent or a mixture of synthetic detergents and an aqueous dispersion of a polymer of styrene or of a substituted styrene or of a copolymer obtained by copolymerising a major proportion by weight of styrene or of a substituted styrene with a minor proportion by weight of a monomer or mixture of monomers which is copolymerisable therewith.

By a liquid synthetic detergent we mean any liquid nonionic, anionic or cationic detergent or mixture of such detergents. As examples of nonionic detergent there may be mentioned for example the condensates of ethylene oxide with the alkylphenols, the fatty alcohols, the fatty acids and the fatty acid mono and dialkanolamides. As examples of the anionic detergents there may be mentioned the alkyl benzene sulphonates, the sulphated alkylphenol/alkylene oxide condensates and sulphated primary and secondary fatty alcohols.

As examples of the cationic detergents there may be mentioned the higher alkyl trimethylammonium halides, the higher alkyl pyridinium halides and the alkyl dimethyl arylammonium halides. There may also be present in the opaque detergent composition any of the materials which are conventionally employed in the formulation of detergent compositions. There may be mentioned for example the builders such as for example tetrasodium pyro phosphate, sodium, potassium, ammonium and alkanolamine hexametaphosphates and pentasodium tripolyphosphate, optical whitening agents, colouring agents, foaming agents and soil suspending agents for example carboxymethyl cellulose, polyvinyl alcohol and polyvinylpyrrolidone.

The opaque liquid detergent composition may contain an aqueous dispersion of polystyrene itself or an aqueous dispersion of a polymer from a substituted styrene, for example, vinyltoluene, ethyl, ethoxy, methoxy, chloro or bromo substituted styrenes or any other of those ring sub stituted styrenes which may be polymerised or copolymcrised in aqueous emulsion by means of free-radical catalysts. Alternatively it may contain an aqueous dispersion of a copolymer obtained by copolymerising a major proportion by weight of styrene or of a substituted styrene with a minor proportion by weight of one or more ethylenically unsaturated monomers which are copolymerisable with styrene or a substituted styrene. As examples of such monomers there may be mentioned acrylamide, methacrylamide, acrylic acid, methacrylic acid, acrylic and methacrylic esters, acrylic and methacrylic nitriles, butadiene and maleic acid.

Particularly valuable for use in the opaque liquid detergent compositions of our invention are aqueous dispersions of copolymers of styrene obtained by copolymerising a major proportion by weight of styrene with a minor proportion by weight of a monomer or mixture of monomers as hereinbefore defined which contain a hydrophilic group. As examples of such monomers there may be mentioned acrylamide, methacrylamide, acrylic acid and methacrylic acid. The monomer containing a hydrophilic group or -a mixture of such monomers comprises a minor proportion by weight of the copolymer and preferably comprises from 1% to 25% of the copolymer.

Aqueous dispersions of such polymers or copolymers may be obtained by methods known in themselves, for example by using conventional emulsion polymerisation techniques.

It is desirable to control the size of the polymer particles in the aqueous disperson so that the maximum degree of opacification of the liquid detergent is obtained. The relationship between particle size and the degree of opacification is complex but is dealt with in a paper by W. Heller and W. J. Pagonis in the Journal of Chemical- Physics, volume 26, number 3 (1957) at page 498 on the basis of Mies theory of light scattering. The opacity of a given suspension is expressed as the specific turbidity (T/C) o where 'r is the turbidity, that is the coefiicient of apparent absorption of light resulting from its scattering, and c the concentration of the solid phase. Table H of the paper sets out the relationship between specific turbidity and two parameters m and a, where m is the ratio ,a M between the refractive indices of the solid and the liquid and a is 1r where D is the diameter of the particles, assumed spherical, and A is wavelength of the incident light. By the use of this relationship it is possible, 5 knowing the refractive index of the detergent composition it is desired to opacify and the refractive index of the polymer or copolymer, to determine the theoretical optimum particle size to give the maximum degree of opacification.

Thus where the polymer is polystyrene having a refractive index of 1.6, and the liquid detergent has a refractive index of 1.4, m becomes 1.143 and the theoretical maximum specific turbidity (T/C)0 is 347 6H1. 1 corresponding to a diameter for the particles of 1.3 microns. If the particle diameter is 0.1 microns the theoretical specific turbidity is 5.7 cm.- and if it is '2.7 microns the theoretical specific turbidity is 191 emf showing a decrease from the maximum in each case.

Although the correspondence between theory and practice is not exact, partly because it is impossible in practice to obtain polymer dispersions having all the particles of the same diameter, the theory is valuable in indicating a size range for the polymer particles in the aqueous dispersions within which the sizes of the particles of the aqueous dispersions giving the best opacification are likely to fall.

In the case of the composition of our invention which contain an aqueous dispersion of a copolymer of a major proportion by weight of styrene with a minor proportion by weight of a monomer containing a hydrophilic group, we prefer that the diameters of the majority of the particles of the copolymer in the dispersion shall fall within the range 0.1 micron to 4.0 microns.

It is preferred that the polymer or copolymer comprises from 0.01 to 5.0% by weight of the total weight of the detergent composition.

In certain cases in order to improve the storage stability of the opaque liquid detergent compositions it is desirable to add to the aqueous dispersion of the polymer or copolymer minor amounts of a water soluble polymer, for example a water soluble cellulose derivative such as a hydroxyethyl or carboxymethyl cellulose, a polyacrylic or methacrylic salt, a polyvinyl alcohol or a starch or starch derivative in aqueous solution.

The opaque detergent compositions may be prepared for example by adding the components of the formulation to water and agitating to obtain a homogeneous composition.

The invention is illustrated but not limited by the following examples in which parts and percentages are by weight.

Example 1 A series of opaque liquid detergent compositions are prepared having the compositions set out in the following table:

4 Example 2 An opaque liquid detergent composition is prepared having the following composition:

Parts by weight Calgon S 10.00 Empicol LZV(SLS) 10.00 Ammonium salt of castor oil fatty acids 10.00 10 styrene/ acrylic acid copolymer at 40% solids 0.01 Water 69.99

Total parts by weight 100 Example 4 If in the opaque liquid detergent composition of Example 3 the 0.01 part of the 90/ 10 styrene/ acrylic acid copolymer at 40% solids are replaced by 0.01 part of a 40% aqueous dispersion of polystyrene a similar opaque liquid detergent composition is obtained.

Example 5 If in Example 1 the parts by weight of the 90/ 10 styrene/acrylamide copolymer at 40% solids in the detergents number from 1 to 8 in the table are replaced by equal parts by weight of a 90/ 10 styrene/methacrylamide copolymer at 40% solids or of a 90/10 vinyltoluene/ aerylamide copolymer at 40% solids similar series of opaque liquid detergent compositions are obtained.

Example 6 If in the opaque liquid detergent composition of Example 3 the 0.01 part of the 90/ 10 styrene/ acrylic acid copolymer at 40% solids are replaced by 0.01 part of a /5 styrene/ acrylic acid copolymer at 40% solids or by 0.01 part of a vinyltoluene/acrylic acid copolymer at 40% solids similar opaque liquid detergent compositions are obtained.

Example 7 Aqueous dispersions of a copolymer of styrene and aerylamide (90/ 10) at 40% solids having different particle size characteristics were prepared. These dispersions were used to prepare detergent compositions having the same composition as Detergent No. 1 of Example 1. The optical densities were determined on the basis of a 0.5% aqueous dilution (by volume) using a 1 cm. cell and a 602 filter. Particle size was determined by electron micro- Detergent Numbers 1 2 3 4 Llssapol NX Sodium dodecylbenzene sulphonate Sodium xylene sulphonate Ammonium dodecylbenzene sulphonate. Ammonium sulphate of nonylphenol eondensed with 5.5 mol. of ethylene oxide.-. Empllan 303 Tetrasodium pyropho ha Ethanol 6401 Glyr-pri n A 90/10 styrene/aerylamide copolymer at 40% solids Water Total parts by weight scopy (total magnification=l0000). The detergent compositions had the following characteristics:

Detergent No 1 2 Q 3 Particle size of copolymer:

Example 8 A dispersion of polystyrene stablilised with an anionic dispersant and having a solids content of 45%, is modified by the addition of a 50% aqueous solution of a hydroxyethyl cellulose, the latter being added to the polymer dispersion in such amount as to give a polystyrene/hydroxyethyl cellulose ratio of 100/5 parts by weight.

This stabilised polystyrene dispersion was then used to opacity a detergent. Whereas the unmodified, anionically stabilised polystyrene readily settled in the detergent mix, the colloidally stabilised particles obtained by the addition of the hydroxyethyl cellulose to the polystyrene showed only a slight tendency to settle on storage.

We claim:

An opaque liquid detergent composition consisting essentially of a liquid synthetic detergent selected from the group consisting of anionic, cationic and non-ionic synthetic detergents or mixtures thereof and an aqueous dispersion of a copolymer of styrene with at least one ethylenically unsaturated monomer selected from the group consisting of acrylamide, methacrylamide, acrylic acid and methacrylic acid, said monomer comprising from 1% to 25% by weight of said copolymer, and said copolymer comprising from 0.01% to 5.0% by weight of said detergent composition in which the majority of the particles of said copolymer have diameters greater than 0.1 micron and less than 4.0 microns.

References Cited UNITED STATES PATENTS 2,689,815 9/1954 Gershon et a1. 260--132 X 3,130,166 4/1964 Schwalley 252-132 X 3,150,098 9/1964 Wilson 252161 X LEON D. ROSDOL, Primary Examiner. S. E. DARDEN, Assistant Examiner. 

